Replace numeric of different length in a string with different text length

Problem: Numeric is of different length could be 1, 200, 1000, 39 99995 etc. And need to replace with a text eg. "Apple" which is of different lenth comapring to the numeric values.

let str: String = "hello i have 1313 object of 10 string class with 1 object, similar to 9999 errors"

Expected Result = "hello i have Apple object of Apple string class with Apple object, similar to Apple errors"

I have tried with below code:

 var originalString: String = "hello i have 1313 object of 10 string class with 1 object, similar to 9999 errors"

    let strippedString: NSMutableString = NSMutableString(capacity: originalString.characters.count)
    var numArray: [String] = []
    var locArray: [NSNumber] = []
    var scanner: NSScanner = NSScanner(string:originalString)
    let numbers: NSCharacterSet = NSCharacterSet(charactersInString: "0123456789")
    while scanner.atEnd == false {
        var buffer: NSString?
        if scanner.scanCharactersFromSet(numbers, intoString: &buffer) {
            strippedString.appendString(buffer! as String)
            numArray.append(buffer! as String)
            locArray.append(scanner.scanLocation)
        }
        else {

            scanner.scanLocation = (scanner.scanLocation + 1)
        }
    }
    for (index, _) in numArray.enumerate() {
        var loc : Int = Int(locArray[index] ) - (String(numArray[index]).characters.count)
        let len = String(numArray[index]).characters.count
        let dupStr = "Apple"
        if(index != 0 && len !=  dupStr.characters.count)
        {
            loc = loc + (dupStr.characters.count - len) + 1
        }
        originalString.replaceRange(originalString.startIndex.advancedBy(loc)..<originalString.startIndex.advancedBy(loc + len), with: dupStr)
    }
    print(originalString)

Swift 2

NSScanner is great, but if you want a simpler solution for this task, you could use componentsSeparatedByString, map, Int() and joinWithSeparator, like this:

let originalString = "hello i have 1313 object of 10 string class with 1 object, similar to 9999 errors"
let tokens = originalString.componentsSeparatedByString(" ")
let newTokens = tokens.map { (token) -> String in
    if let _ = Int(token) {
        return "Apple"
    }
    return token
}
let result = newTokens.joinWithSeparator(" ")
print(result)

Prints:

hello i have Apple object of Apple string class with Apple object, similar to Apple errors

There's also a short version for the mapping:

let newTokens = tokens.map { Int($0) != nil ? "Apple" : $0 }

Swift 3

componentsSeparatedByString(_:) is now components(separatedBy:), and joinWithSeparator(_:) is now joined(separator:).

let tokens = originalString.components(separatedBy: " ")
let newTokens = tokens.map { Int($0) != nil ? "Apple" : $0 }
let result = newTokens.joined(separator: " ")